Effect of pH and Heat Treatment on the Antioxidant Activity of Egg White Protein-Derived Peptides after Simulated In-Vitro Gastrointestinal Digestion.

Priyanka Singh Rao,Sophie Alvarez,Emerson Nolasco,Kaustav Majumder,Akihiro Handa,Michael J Naldrett

doi:10.3390/antiox9111114

Abstract

The study aimed to analyze pH and heat treatment’s effect in modulating the release of peptides with antioxidant activity after simulated gastrointestinal (GI) digestion of Egg white powder (EWP). EWP samples with neutral (EWPN) and alkaline (EWPA) pH were heat-treated at 20, 60, and 90 °C and analyzed for protein aggregation, solubility, and GI digestibility. Heat treatment decreased solubility and induced protein aggregation, which was higher for EWPN as compared to EWPA. The unfolding of EWPA proteins at 60 °C exhibited a higher GI digestibility and antioxidant activity via Oxygen Radical Absorbance Capacity (ORAC) assay as compared to EWPN. Interestingly, a reverse trend was observed in the cellular antioxidant assay, and the GI-digest of EWPN exhibited a higher antioxidant activity. The LC-MS/MS analysis are in concordance with cellular antioxidant activity assay and showed a higher intensity for peptides with potential antioxidant activity in the GI-digest of EWPN. The results indicate that heat treatment but not the pH is a critical factor in improving the protein digestibility and releasing peptides with antioxidant activity after GI digestion.

Highlights

Chicken eggs are an essential part of the human diet
Our results indicate that the addition of egg white hydrolysate could significantly (p < 0.0001) reduce the Reactive Oxygen Species (ROS) generation at all concentrations when compared to the positive control (PC) (Figure 3)
The digestibility of egg white powders treated at different heating temperatures was studied by in vitro digestion followed by the digests’ analysis

Summary

Introduction

Chicken eggs are an essential part of the human diet. Economical, accessible, and utilized in a wide range of food preparations globally. A 16 percent increase in per capita egg consumption has been observed in the United States over the past 20 years. The use of egg products, especially the dried egg white powder, has increased substantially [1]. The whole egg is composed mainly of egg white (63%) and egg yolk (27.5%) [2]. Egg white proteins have shown high gastrointestinal (GI) digestibility, recognized as a critical dietary source of essential amino acids vital for human growth and development [3]

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Conclusion